BOSTON (CBS) – From weight-loss breakthroughs to skin creams that reverse aging, we’ve all seen those online deals for a so-called free trial. But that temptation to test out a free product can actually cost customers big time.

Just ask Debbie Wagner.

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She spotted a new face cream online and decided to give it a try. She only had a to pay a few bucks for shipping. When the sample of Dermiva arrived, Wagner was not impressed.

“It was like a watery cream. It was nothing that you would like to put on your face,” she said.

With no plans to order more, Wagner says another shipment of face cream arrived a month later, along with an eye serum she never ordered and a bill for $160. Buried in the fine print, that free trial actually auto-enrolled Wagner for an expensive, monthly subscription plan.

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Complaints about these “free” trials more than doubled between 2015 and 2017, according to the Better Business Bureau. And it costs customers $1.3 billion in unexpected charges.

Beginning April 12, Mastercard will require merchants to get approval at the end of a free trial and before bills begin for a paid subscription. Companies will also need to email or text a receipt and instructions on how to cancel the product.

Debbie Wagner incurred expensive charges after signing up for a free trial. (WBZ-TV)

“If I could scream from the rooftops, I’d tell people please, please, please don’t do free trials,” Wagner warned.

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American Express also requires retailers to get customer consent on recurring charges. But, the best advice is to keep a constant eye on your accounts and if you see something suspicious, take action quickly.

Kate Merrill